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Hello and Thank You for your help,

     My smoke unit is not pictured in the PS3 upgrade instructions. Can anyone tell me what needs to be cut, removed or re-wired? The fan is completely wired separately on my board I understand that portion of the instructions. Just need help on the heating element.

Thank You Again,





Images (1)
  • Smoke Unit
Original Post

There is no ground for the smoke unit wiring, so where does that wire go?  It's likely not used with the PS/3 upgrade.

Note that for PS/2 or PS/3 electronics, there are NO chassis ground connections except for the input track power on the 7-pin connector on the PS/2 or PS3/2 board.  You have to make sure no other connections get grounded, that will be very bad for the electronics.

Hi John,

      A picture is worth a 1000 words, so this is the wire I am speaking of, it runs to a screw holding the constant lighting board in place. There is another wire from the constant lighting board to the same screw. I have two ground wires, one in the tender and one in the locomotive.

Thank You Again!


Images (2)
  • smoke unit ground wire 2
  • smoke unit ground wire

What engine is that?  Have you measured the resistor ohms of the smoke elements?   MTH PS-1 smoke does have an AC ground, but it feeds the PS-1 smoke electronic board.  Your smoke does not have the traditional PS-1 board.  So it is getting power from the CV board for smoke fan and it looks like the rectifier also for elements. 

The CV board is already grounded with the brown wire to the center mounting screw of the CV board.  So you need to remove that brown wire from smoke unit.  It looks like that is on DC side of the CV board.  Not 100% sure, but looks that way and needs to be metered.

Either way Johns advice on the Smoke PCB mod is right, but you better make sure the individual elements are 16 ohms, or the parallel connection reads 8 ohms.  I would remove the brown and orange wires to the smoke unit and trace where they wind up.  The Smoke switch on the engine comes out too and is part of that circuit.  G

George, I assumed, perhaps falsely, that the smoke unit was wired to the remote smoke control board, I see a lot of them I pull out of stuff wired with a remote board.

I found one in my parts box that is like his example with the thermistor and the resistors are 24 ohms!  Good catch on measuring those, they'll have to be swapped out for the proper resistors.   No damage would have occurred, but I suspect smoke performance wouldn't have been all that impressive. 

It appears this unit was designed to connect directly to track power and just the thermistor controls switching in the second element based on current through the smoke unit.

That is why I wanted model number.  I have only worked on one of those and it was so long ago I can't remember what it was.  As a tech we trace wires and have familiarity with AC versus DC.  His second picture showed fan and element attached to cv board.  Could very well have element attached to the AC connection side of the CV board, via the switch.  G

Just one more case where seeing it in the locomotive would have made it easy to verify what you have.   Seeing what the smoke unit actually consists of, it does seem that the CV board ran the fan and the smoke element connected directly to the track power.  I actually took that one out and tried it, worked great on track power with a DC supply for the fan.

Now that we know what we're dealing with, my modification instructions were valid, but the two resistors will also have to be changed to the standard MTH PS2/3 16 ohm resistors.

Last edited by gunrunnerjohn

Sorry guys I have been neglecting my emails and just noticed you have been writing me.

This is a Premier New York Central Empire State Express from back in 95; model number MT-3016L.

Smoke output from the engine after the upgrade is pretty low; I was thinking it might need a re-wick from sitting the past 20 or so years, but maybe it does need the resistors replaced. Let me know what else you might need to assist.

As for the conversion all other locomotive functions are working as anticipated after an PS upgrade.

Thank You,



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